Gyroscopes are used for measuring and/or maintaining orientation. As used herein, a “gyroscope” is a sensor configured to detect and measure the angular motion of an object relative to an inertial frame of reference. Further, as used herein, an “inertial frame of reference” may be a coordinate system or set of axes that is non-accelerating. In other words, an inertial frame of reference is a frame of reference in which Newton's first law of motion is true. Newton's first law of motion states that the velocity of a body remains constant unless the body is acted upon by an external force.
A Coriolis vibratory gyroscope (“CVG”) is configured to be driven to vibrate along a first axis. Vibration along the first axis while the Coriolis vibratory gyroscope is being rotated about a fixed input axis not co-aligned with the drive axis, for example, perpendicular to the drive axis, generates a Coriolis force that induces vibrations along a second axis. These vibrations may be measured and used to determine an angular velocity for the rotation of the Coriolis vibratory gyroscope about the fixed input axis.
However, bias may contribute to the measurements of the angular velocity. Bias may be the error in the measurements due to factors such as, for example, without limitation, temperature, part inconsistencies, and other suitable factors. Calibration of these gyroscopes during manufacturing of the gyroscopes may be less accurate than desired.
For example, calibration of these gyroscopes during manufacturing processes may use test data as compared to substantially real-time data. In particular, these calibration techniques may not take into account the effects of the temperature in the environment in which a gyroscope is being operated and/or inconsistencies that may develop over time from the time at which the gyroscope was manufactured. Further, some currently available systems for compensating for this bias may be unable to reduce the bias from these vibration measurements to within selected tolerances.
Therefore, it would be desirable to have a method and apparatus that takes into account one or more of the issues discussed above as well as possibly other issues.